// Department类
public class Department {
    private List<Instructor> instructors = new ArrayList<>();
    private List<Subject> subjects = new ArrayList<>();

    public void addInstructor(Instructor instructor) {
        instructors.add(instructor);
    }

    public void addSubject(Subject subject) {
        subjects.add(subject);
    }

    public List<Instructor> getInstructors() {
        return instructors;
    }

    public List<Subject> getSubjects() {
        return subjects;
    }
}
